Autonomic Nerves in Head Anatomy
1. Nerve (vidian) of pterygoid canal
2. Deep petrosal nerve
3. Greater petrosal nerve
4. Otic ganglion
5. Chorda tympani nerve
6. Superior cervical sympathetic ganglion
7. Submandibular ganglion
8. Pterygopalatine ganglion
9. Ciliary ganglion
Comment: This schematic shows the 4 parasympathetic ganglia
in the head. The ciliary ganglion receives preganglionic parasympathetic fibers
from the oculomotor nerve. The otic ganglion receives preganglionic
parasympathetic fibers that arise in the glossopharyngeal nerve. The
pterygopalatine and submandibular ganglia receive preganglionic
parasympathetics that originate in the facial nerve.
Preganglionic sympathetic fibers arise
from the upper thoracic spinal cord levels. They ascend the sympathetic trunk to
synapse on postganglionic neurons in the superior cervical ganglion.
Postganglionic sympathetic fibers
travel on blood vessels or adjacent nerves to reach their targets. These
sympathetic postganglionic fibers are largely vasomotor in
function.
Clinical: A unilateral lesion anywhere along the pathway of
the preganglionic sympathetic axons, from the upper thoracic spinal cord levels
(T1-4) to the superior cervical ganglion (where they synapse), or beyond this
ganglion (postganglionic axons), can result in ipsilateral Horner’s syndrome.
Its cardinal ipsilateral features are miosis (constricted pupil), slight ptosis
(drooping of the eyelid due to loss of the superior tarsal muscle), anhidrosis
(loss of sweat gland function), and flushing of the face (unopposed vasodilation).
